Photographic layers



United States Patent 3,211,556 PHOTOGRAPHIC LAYERS Walter Anderau, Aesch, Switzerland, assignor to Ciba Limited, Basel, Switzerland, a company of Switzerland No Drawing. Filed Mar. 13, 1964, Ser. No. 351,839 Claims priority, application Switzerland, Mar. 9, 1960,

16 Claims. (CL 96-99) This is a continuation-in-part of my copending patent application Ser. No. 93,835, filed March 7, 1961, now abandoned.

The production of a colored photographic image by the silver dyestuff bleaching method is based on the discovery that an azo-dyestuff, one of the wide range of azo-dyestuffs with which the layer-forming substance, especially gelatine, can be colored, is bleached out depending on the quantity of image-forming silver present in the layer. The silver image is usually produced by exposing the light-sensitive, and in some cases sensitized, silver halide present in the colored layer, and developing and fixing the silver image.

The method can be applied to a colored layer produced by coloring the layer-forming substance with the azodyestufI before the layer is formed or by coloring the finished layer on its support. The method can also be applied to multilayer photographic materials.

For example, three colored layers may be applied to a transparent or white pigmented support or to baryta paper. Next to the support there is, for example, a selectively red sensitized silver bromide emulsion colored with a green-blue dyestuff, then on this layer there is a selectively green sensitized silver bromide emulsion colored purple, and finally a selectively blue sensitive layer colored yellow. By copying an original color picture (an integral or additive copy) with an ordinary light source, for example, an incadescent tungsten electric lamp or copying color component record with selectively colored light, the silver bromide is exposed at the appropriate areas of the layers. After the exposure the development with ordinary developers, and the fixing, each of the colored layers contains a component color record in the form of a negative silver image in a homogeneously colored layer.

By means of a suitable dyestuff bleaching bath, for example, an acid aqueous solution of potassium bromide and thiourea, and a suitable catalyst, such as 2-amino-3- hydroxyphenazine, azo-dyestuff present in each layer is bleached out in accordance with the image, so that, in dependence on the quantity of image silver present (and in the simplest case approximately in proportion to the quantity of such silver), the azo-dyestuifs are reduced to practically colorless decomposition products according to the following equation:

R represents the radical of the diazo-compound obtainable from the diazo-component R NH and R represents the radical of the coupling component HR By the splitting reaction the diazo-component is regenerated, and an amino-compound H N-R is formed from the radical of the coupling components. In the case of disazoor polyazo-dyestuifs there are also obtained as fission products diamines, for example:

Unconsumed image silver is removed in known manner, for example, with Farmers reducer, and also the silver bromide formed in the bleaching process. In this manner a positive copy of the originial is obtained.

The present invention is based on the observation that it is advantageous to use azoxy-dyestuffs, instead of or in addition to azo-dyestuffs, in photographic layers to be used for the silver dyestu'ff bleaching method. ,Accordingly, the present invention provides photographic silver halide gelatine layers suitable for the silver dyestufi bleaching method, containing as image dyestuffs dyestuifs that contain at least one azoxy group. For the azoxygroup there is used herein the formula which reflects reality better than the formula which contains two trivalent ntirogen atoms.

With azoxy-dyestuffs yellow, red, purple, blue and green-blue tints are produced .not only on textiles, as is known, but also in photographic layer, especially those of gelatine. The azoxy dyestuffs preferably contain at least one group imparting solubility in water.

The preparation of azoxy-dyestulfs is adequately described in the literature. They are obtained, for .example, by condensing nitro compounds with amines as follows:

or by the reduction of-nitro-compounds under very special conditions as follows:

In the latter case the reduction is generally carried out with the use of arseneous acid or with the use of glucose in an alkaline medium.

Inthis manner.azoxy-polyazo-dyestufis can also be obtained, that is to say dyestuifs which contain, forexample, one azoxy group and at least two azo groups. These dyestuffs produce blue tints. There are also known azoxypolyazo-dyestuifs which contain groups-capable of forming metal complexes and are, therefore, capable of forming complex heavy metal compounds. Such azo-azoxydyestuifs capableof forming metal complexes, andazoxydyestuffs free from azo groups and which are capable of forming metal complexes, may contain as the complexforming group, for example, a salicylic acid radical, and may be used in the non-metallized condition to produce the colored layers,.and converted, after the silver dyestuff bleaching operation, into the complex heavy metal compounds, for example, by means of a solution of copper acetate or another agent yielding metal.

Instead of converting the-dyestuffs subsequently into their complex metal compounds, photographic materials may be colored with the pre-formed complex metal compounds prepared in substance, for example, silver halide emulsions so colored may be used for casting.

The complex metal compounds, and especially the complex copper compounds, whether prepared in substance or produced in the colored layer, are distinguished by their very good fastness to light. They can be bleached out completely by the silver dyestufi bleaching method at the areas having the highest density of silver, and this could not be foreseen. It is necessary to take into account the fact that the complex metal compounds of metals having atomic numbers from 22 to 29, and especially the complex copper compounds yield deeper tints thando the 3 i 4 metal-free dyestufis. The azoxy group undergoes reduc- This azoxy-disazo dyestuif yields a blue tint having an abtlon in accordance with the following equation sorption maximum at 620 m The fastness to light of the R1 N=N RI (mg GHBI blue color image produced by the silver dyestufI bleaching process with this dyestulf can be considerably im- RFNH2 H2N=R2 H20 proved by treating with a solution of 2 to 5% strength of an agent yielding copper, such as sodium copper tartrate.

This dyestuif itself possesses a remarkably low capacity for diffusion so that it has hardly any tendency to migrate into an adjacent layer. However, the resistance to diffusion in gelatine can be still further improved by suitable additions, for example, a guanidine base.

In general azoxy dyestufis having a good resistance to diffusion can be produced by incorporating into the molecule of the dyestuif a radical which imparts resistance to diifusion. Thus, in the aforesaid dyestuif No. 3 the primary amino group may be replaced by groups of the so that a larger quantity of image silver is required to bring about the reduction than in the case of the azo group. This greater consumption of image silver, as compared with the consumption required for reducing the azo group, leads to relatively flat color gradations, which are 10 very desirable for certain copying processes. For the purposes of this invention it is of advantage to use azoxy-dyestuifs which are homogeneous compounds and contain a definite small number, for example, one or two azoxy groups in the molecule. They may contain, for example, an atomic grouping of the formula formula N=NR-N=N I 8 /R4 in which R represnts a benzene or naphthalene nucleus, 0 which contains in a position vicinal to the azo group a R, substitutent capable of taking part in the formation of heavy metal complexes, for example, a carboxylic acid, carboxy-methoxy methoxy or hydroxyl group. in which R4 re presents a hydrogen atom or an alkyl group, There g f belpw a few dyestuffs Smtable for the and R represents an acyl, sulfacyl or aracyl group or purposes 0 t e mventlon' the chain of an aliphatic or hydro-aromatic radical. Thus, No. 1 The yellow dyestutf of the formula for example, R may represent a'benzyl radical, for ex- 0 o S0311 H038 which is obtainable by condensing 4:4'-dinitro-stilbene ample, a dichlorobenzyl radical, a benzoyl radical, a didisulfonic acid with aniline in the molecular ration 1:2. chlorobenzoyl radical, a para-toluene-sulfonyl radical, or No 2 The red dyestufi of the formula an aliphatic hydrocarbon radical, whlch may be inter- (2) HO OO-HzC-O OCHzCO OH N==C o C=N H, Hal This dyestuff dyes gelatine yellowish-red and can be conrupted by hetero atoms, Such as an amyl, n{mwdecyh verted into its complex copper compound which is very octadecenyl, dodecyl-hydroxypropyl or stearoyl radical. fast to hght and yields blmsh'red t1 Furthermore, there may be used, instead of the dye No. 3 The blue dyestufi of the formula stuif No. 3 or another azoxy-dyestuif, containing ortho- (3) HgN 0H EEO-(l) 0-011 HO NH;

which is obtainable from the nitro-monoazo-dyestufi of the formula hydroxy-ortho-methoxy-azo groupings, the corresponding ortho:ortho'-dihydroxyazo-metal complex compound 3 N OH HaC-O obtainable in substance by metallization accompanied by demethylation. From dyestuif No. 3 the following dyestuff can be obtained in this manner.

No. 4. The tint of this dyestufi is changed considerably L towards green-blue as compared with the tint of dyestufi How No. 3. Dyestufl No. 4 corresponds to the formula 4 11,1 OCu )-ou 0 Nrn 1 1103s s03 by reduction with the aid of heat with glucose in a soluits absorption maximum in gelatine is at about 670' mu,

tion rendered alkaline with an alkali metal hydroxide. It can also be completely bleached out well by the silver 3,211,556 .5 6 dyestuff bleaching method at the areas having the maxior further sulfonic acid groups. As diazo components mum density of silver, and it has an excellent fastness to of the kind defined there may be mentioned, for example, light. The bleaching out of this dyestuif can be still further improved by extracting the dyestuif at the boil Z-amino-1-hyd Y- acid, with hydrochloric acid or a cyanide to remove the copper 2-ami110-1-hYdf0XY-5-chlorobellzene-6-sulf0nic acid bound in complex union, and, after the bleaching oper- Z-amiIIO-1-hYdI0XY5-chlorobenlene-4-sulfonic acid, ation reintroducing the copper into the metal-free dyestuff Z-amino-1-hydroxy-4-methylbenzene-6-sulfonic acid, by treatment with a bath containing a water-soluble -amin y 0 y acid, oopper compound. 2-amino-1-hydroxy-6-nitrobenzene-4-sulfonic acid and NO 5 The blue dyestufi of the formula 10 Z-ammo-1-hydroxy-4-mtrobenzene-6-sulfon1c acid. (5) H21? (EH HOOC COOH H? NH2 Ho s N=N IfiT=N N=N -SO H HO 3 SOSH This dyestuif gelatine blue and is bleached out com- The coupling components of Formula 9 may also conpletely by the usual silver dyestulf bleaching baths at the tain further substitutents, for example, a methyl group areas of maximum density of silver. The above remarks in para-position to the methoxy group, but more espewith regard to metallization in connection with dyestufi's cially an ethoxy group or a methoxy group in the said Nos. 3 and 4 also apply to this dyestuff. position. As examples there may be mentioned:

In addition to the azoxy-dyestulfs listed under (1) to (5) above, those described hereinafter under A, B and 25 1 ammo g methoxybfinzene 1-a mino-2-methyl-S-methoxybenzene,

((13 are tafaitliculgrlwvaluzltlblg as image dyestuffs in the silver 1 aminO 2 ethoXy 5 methoxybenzene and yes u eac ma met 0 l-amino-Z:S-dirnethoxybenzene. A. The azoxy dyestuffs of the formula (6) (l)-Cu(|) |)Cu(|) H OaS=R4N=NR5-N=II 'IQ C H: C HQlfiT=N-R5N=NR4S 0 3H 0 0 $0311 H038 wherein R and R each represent a moncyclic benzene Specially good results are generally obtained with radical bound in ortho-position to the azo group and the azoxy dyestulfs of the formula (10) o 0u 0 (I)-Cu 0 HO s o 0 so H a 5-2 s oan 1103's zb a OCuO-group, the azo and azoxy groups being in which Z represents an alkyl group containing at most bound in para-position to the benzene radicals R 2 carbon atoms.

The azoxy dyestulfs of Formula 6, some of which are known, are obtained by condensing 4:4-dinitrostilbene- B. The azoxy dyestuff of the formula 11 CCu-O OCu--O RtHN N=N=I;I=N=N=N NHR o SOBH HOaS- 2:2-disulfonic acid in a molecular ratio of 1:2 with in which R represents a monocyclic benzene radical. aminoazo dyestuffs of the formula The azoxy dyestulf of Formula 11, some of which are known, are obtained by coupling diazotized 5-nitro-:2- amino-'l-hydroxybenzene in an alkaline medium with a HO3SR N=N R5 NH2 2 phenylamino-S-hydroxynaphthalene-6-sulfonic acid of the formula in which R; and R have the meaning given above and then metallizing with an agent yielding copper accom- (12) OH panied by demethylation of the methoxy groups. The aminoazo dyestuffs are obtained by coupling diazo com- RtHN- pounds of orthohydroxyamines of the formula SOQH (8) (PH HO3SR NH in which R has the meaning given above, condensing Wlth ammes of the formula the nitroazo dyestuif with the formation of an azoxy (9) H3O-o group from two nitro groups and then coppering. The I 2 phenylamino-8-hydroxynaphthalene-6-sulfonic acids used as coupling components 1n this process may conwhich couple in paraposition to the amino group, wheretain further substituents in the phenyl radical, for exin R and R have the meanings given above. ample, halogen atoms, for example, chlorine, alkyl groups, The amines of the Formula 8 may contain additional for example, a methyl group, alkoxy groups, for example, substituents, for example, halogen atoms such as chlorine, a methoxy group, acidic groups imparting solubility in alkyl groups such as ethyl or methyl groups, nitro groups Water, for example, carboxylic acid groups, carboxy- 7 methoxy groups HOOCCH 'O-) or especially sulfonic acid groups. As examples there may be mentioned:

2-phenylamino-S-hydroxynaphthalene-6-sulfonic acid-4'- carboxylic acid,

2-phenylamino-8-hydroxynaphthalene-6 3 '-disulfonic acid and 2-phenylamino-S-hydroxynaphthalene-6-sulfonic acid.

The photographic layers that contain azoxy dyestuffs of the formulae 6 or 11 can be of the usual composition and can be prepared in known manner. The supports for the silver halide layers can be, for example, glass for duplicate positives, or they can be made of cellulose esters, or they can be opaque, white-pigmented films, baryta paper or reflecting supports.

In the conventional silver dyestuif bleaching process a positive copy is obtained by copying a transparent, colored master image on a dyed gelatine layer containing silver halide. By using, in the silver dyestuff bleaching process, copying material dyed black with transparent dyestuffs, positive (rectified) copies are obtained in a simple manner from a black and white original. When a colored positive master image is copied on such a silver halide layer dyed a transparent black that, if necessary, may be sensitized to the color concerned, a positive black and white copy of the colored original is obtained, the grey tones being graduated. The azoxy dyestuffs of Formulae 6 and 11 are specially suitable for the production of such copies.

The black dyestuffs used in the silver dyestuffs bleaching process must possess a wide range of properties. A high degree of light fastness is required and the dyestuffs should be capable of being bleached to neutral grey tones. They must be non-diffusing or must be capable of being rendered non-diffusing with precipitating agents, for example, guanidines. The dyestuffs of Formulae 6 and 11 meet these requirements to a large extent.

Very strong acid baths are used in the course of the bleaching process which means that the copper-containing dyestuffs are partially demetallized. It is, therefore, of advantage to treat the dyestuffs with a copper-yielding agent in a slightly acid to alkaline medium at the end of the bleaching process in order to convert the demetallized portion back to the complex copper compound.

C. The azoxy dyestuffs of the formula wherein R represents a monocyclic benzene ring bound to the azo group in 1-position and to the azoxy group in 4-position and containing in 2-position a substituent selected from the group consisting of an alkoxy group and a hydroxyalkoxy group containing at most 5 carbon atoms, and R and R each represents the radical of an 8-hydroxy-naphthalene-disulfonic acid bound to the azo group in its 7-position and containing in its l-position a further substituted amino group.

The dyestuffs of Formula 13 may be prepared by treating a nitromonoazo dyestuff of the formula in which R represents a benzene radical bound in the 1-position to the azo group and in the 4-position to the nitro group and containing in the 2-position an alkoxy group or a hydroxyalkoxy group with at most 5 carbon atoms, and R has the meaning given above, with a reducing agent which is capable of reducing a nitro compound to an azoxy compound with the linking of two molecules. This method is particularly suitable for the 8 preparation of symmetrical compounds of the Formula 13(R =R Unitary asymmetrical as well as symmetrical dyestuffs of the Formula 13 may be prepared by coupling a tetrazo compound of a diamine of the formula on either side with one of two different aminohydroxynaphthalenedisulfonic acids, or on each side with an identical azo component of this kind. In the Formula 15 R represents a benzene radical bound in the l-position to the amino group and in the 4-position to the azoxy group and containing in the 2-position an alkoxy group or a hydroxyalkoxy group with at most 5 carbon atoms. The compounds of the Formula 15 may in their turn be prepared by reducing a l-acylamino-Z-alkoxy- 4-nitrobenzene or a 1-acylamino-2-hydroxyalkoxy-4- nitrobenzene to form an azoxy compound of the formula in which R, has the meaning given above, and by subsequent hydrolysis of the acylamino group.

The 1-acylamino-2-alkoxy-4-nitrobenzenes or l-acylamino-2-hydroxyalkoxy-4-nitrobenzenes used for the preparation of the diamines of the Formula 15, and the corresponding amino compounds employed for the preparation of the nitromonoazo dyestuffs of Formula 14 contain in the ortho-position to the acylamino group or to the amino group for example a methoxy, n-propoxy, isopropoxy or n-butoxy group. As a rule ethoxy and hydroxyethoxy groups are particularly advantageous. Further substituents, for example a methyl or ethyl group or a chlorine atom, may be present in these compounds but are not necessary.

The 8-hydroxynaphthalenedisulfonic acids with a further substituted amino group in the l-position, used as azo components for the preparation of the dyestuffs of Formula 13 according to the methods shown, contain the sulfonic acid groups preferably in the 3,6- or 4,6-position. The amino group in the 1-position is further substituted, for example by alkyl groups, such as ethyl or methyl, by benzene radicals which may themselves bear further substituents, by cycloalkyl radicals such as cyclohexyl, or advantageously by acyl radicals. The acyl radicals are derived from carboxylic acids or sulfonic acids, especially those of the benzene series, in which latter case the benzene nuclei may bear further substituents, for example chlorine atoms or alkyl radicals, particularly methyl groups. The following examples may be mentioned:

1-phenylamino-8-hydroxynaphthalene-3,6-disulfonic acid, 1-phenylamino-8-hydroxynaphthalene-4,6-disulfonic acid, 1-cyclohexylamino-8-hydroxynaphthalene-3,6-disulfonic acid, l-cyclohexylamino-S-hydroxynaphthalene-4,-disulfonic acid, l-benzoylamino-8-hydroxynaphthalene-3,6-disulfonic acid, 1-para-toluenesulfonylamino-8-hydroxynaphthalene-3,6-

disulfonic acid, 1-para-toluenesulfonylamino-8-hydroxynaphthalene-4,6-

disulfonic acid, 1-para-toluenesulfonylamino-8-hydroxynaphthalene-3,5-

disulfonic acid, 1- 3 '-carboxy-4'-hydroxybenzenesulfonylamino) -8- hydroxynaphthalene-B,6-disulfonic acid.

From the above it is clear that for the present invenmay contain further layers which do not contain an; tion the azoxy dyestuffs of the following formulae are image dyestuffs. The gelatine layers colored with the especially suitable: dyestufls of Formula 13 show particularly pure tints and especially favorable absorption curves. (17) A OH X X Ho 1?.

Y S0311 HO3S- Y Acyl-NH 011 If X HO HN-Acyl HO3S- S0311 HO3S SOQH RpS -NH on 1|! 2'? Ho HNo sR9 HOaS soan Hmss03H In these formulae, X represents an alkoxy or hydralkoxy A few prescriptions for the preparation of some dyegroup with at most 5 carbon atoms, A and A each repstuffs of Formula 13 are given below, In these prescripresents a further substituted amino group, R represents tions and in the subsequent examples the parts and pera monocyclic benzene radical, and in each naphthalene centages are by weight unless otherwise stated. radical of the Formula 17 one Y stands for a hydrogen atom and the other Y for a sulfonic acid group. (6) 76.5 parts of the nitroazo dyestulf, obtained by cou- The dyestuffs of Formulae 13, 17, 18 and 19 may be pling 1-amino-Z-ethoxy-S-nitrobenzene with l-toluenesulprepared in a conventional manner known per se, In fonylamino-S-hydroxynaphthalene-3,6-disulfonic acid in order that the coupling may take place in the 7-position, alkaline medium, are reduced in 5 to 10 minutes at a that is to say in vicinal position to the hydroxyl group temperature between 75 and 90 C. in 2000 parts of water of the hydroxynapthalene compound, the reaction is and 100 parts of an aqueous sodium hydroxide solution of carried out in an alkaline medium. The reduction of by volume with 17 to 18 parts of glucose, dissolved the nitro dyestuffs to form the azoxy dyestuffs is adin 60 parts of water. The azoxy dyestuif of the formula rncOsm-rvn on mo (|)-C2H5 H0 neg-msOon,

H0 s so H HOsS- SO3H vantageously performed with glucose in an aqueous is formed in very good yield and can be separated by sodium hydroxide solution. the addition of sodium chloride. It dissolves in water According to the process of the invention these dyestufls with a greenish blue shade. When the dyestufi is disare present in photographic layers for the silver dyest f solved in gelatine, the solution shows a green-blue layer bleaching process, These materials may be constituted with an absorption maximum of 640 m,u. and prepared in a manner known per se. The silver The dyestuffs shown under (7) to (9) below may also halide emulsion layers colored with the green-blue dyeb prepared b thi method.

stuffs may advantageously be sensitized to red light and form a constituent of a multilayer material, suitable for (7) The dyestuff of the formula HO3S H033- SOzH SO3H the production of multicolored prints, which contains in Absorption maxima in gelatine at 640 and 690 my.

addition to this green-blue layer at least one magenta (8) The dyestuff of the formula @NH OH HaC-O o-on, H0 FIN-O so3H H038 HOQ S SOsH layer sensitized to green light and a yellow layer, and Absorption maximum in gelatine at 620 my 1 1 (9) The dyestuff of the formula 23 H=C-CH2 SOaH HOaS Absorption maximum in gelatine at 620 m (10) l-acetylamino-2-methoxy-4-nitrobenzine is converted at 40 to45 C. with zinc dust in ammoniacal ethanol solution into the azoxy compound of the formula resulting dyestuff of the formula G a a HOaS- SOaH colours gelatine green-blue shades.

Moreover the following dyestuffs which are similar in constitution to those of Formula 13 and can be prepared in analogous manner may be used in accordance with this invention:

EEC-0E2 N N ON N ON N I CHf-C HOaS- The CHrOHg H0 HN-CH The following examples illustrate the invention.

Example 1 6 grams of dyestuff No. 3 (see above) are dissolved in 550 cc. of Water, the solution is mixed with a red sensitized silver bromide gelatine emulsion, and the homogenized mixture is cast as a layer on a suitable support, for example, an acetyl-cellulose film having a substream layer, so that the dry layer contains 15 milligrams of silver in the form of silver bromide and 7 milligrams of dyestuff per square decimeter.

The resulting blue layer can be used as such or it may be used as part of a three-layer material. The layer is exposed behind a colored diapositive or beneath a positive component color image to red light. The exposed layer is developed with a developer containing 0.75 gram GH -CH; 0-0H HO HN-C (JH,

GHQ-C l l I ter, fixed with sodium thiosulfate solution of 20% mG-OsW-I n on EEC-(i) When it is desired to use layers colored with azoxydyestuffs to produce matrices for an imbibition process, dyestuffs that difiuse well are desired. On the other hand, when the silver dyestuff bleaching method is used for the production of multi-color pictures a three-layer material is required, in which the several dyestuffs are as resistant as possible to diffusion and are yet water-soluable. The water-solubility is imparted by the usual groups imparting solubility in water, advantageously sulfonic acid and/ or carboxylic acid groups. A good resistance to diifusion can be imparted by introducing the substituents mentioned above in connection with dyestufi No. 3 or by converting the too easily diffusible dyestuff acid or akali metal salt into a non-diffusing salt, for example, with an organic base or a biguanide. These expedients may of course be used in combination.

The azoxy-dyestuifs can also be used for incorporation in so-called droplet-emulsions (packed emulsions) or for mixed grain emulsion systems.

l V o soarr strength, and then rinsed for one minute with water. The layer is advantageously hardened with formaldehyde solution of 4% strength, and then washed. The silver bleaching bath contains, for example, cc. of hydrochloric acid having a density of 1.19, 12.5 grams of potassium bromide and 10 grams of thiourea dissolved in one liter of water, and if desired, 0.1 gram of dimethylquinoxaline. The bleaching process takes 8 to 15 minutes, and then the layer is washed for five minutes. The layer is then treated in a silver bleaching bath to convert the silver into silver halide. This bath contains, for example, 100 grams of crystalline copper sulfate, 100 grams of sodium-chloride and 50 cc. of hydrochloric acid (density-=1.19) in one liter of water. The treatment in this bath lasts 3 to 8 minutes. The layer is then washed for five minutes and fixed for 3 to 5 minutes in a bath containing 200 grams of sodium thiosulfate in one liter of water. The layer is finally washed for 10 minutes. In order to increase the fastness to light of the dyestuff the layer is after- 13 14 treated with a copper acetate solution of 2.5% strength there is obtained a blue-red image having a somewhat for 10 minutes, and is then washed for one minute. purer tint and which is fast to light. There is obtained a blue component color image of very By using in this example, instead of the aforesaid dyegood fastness to light. stuff No. 2 the same quantity of the yellow dyestutf No. Example 2 1 and otherwise following the same procedure, a yellow componentimage is obtained. 15 grams of dyestuff No. 2 are dissolved in the form of the non-coppered sodium salt in 1000 cc. of water at Example 3 80 C. The solution is rapidly cooled to 40 C., and 2 parts of one of the salt-free cupriferous dyestuffs of mixed with 1000 grams of a gelatine solution of the formulae (29) (|)Cu (I) (')Cu O H5 o 2% I 38 0CH3 SOaH HO3S HgC-O SOEH strength having a temperature of 40 C., and the whole or (30) O-Ou (I) O Cu O HOaS SOaH O HOaS 3 0311 is stirred for a short time. The colored gelatine is then are dissolved in 100 parts of water at 40 C., and the mixed with 1000 grams of a silver bromide gelatine emulsolution is mixed with a preparation obtained by allowing sion, which may be yellow-green sensitized and contains 25 to 30 parts of gelatine to swell in 300 to 600 parts and a quantity of silver bromide such that, after being cast then melting the gelatine at 40 C. The amount of gelaand dried the layer contains 15 milligrams of silver per tine used depends on the support on which the prepared square decimeter. The layer so produced can be used as emulsion is to be cast. 300 to 600 parts of a silver :brosuch or as one of the layers of a three-color material. mide emulsion that can be orthochromatically or pan- After being exposed the layer is treated as follows: 30 chromatically sensitized are added to the colored gelatine.

(1) A silver image is developed for 8 minutes at C. Furthermore, water to reduce the viscosity, aqueous soluwith a bath which contains dissolved in 1000 cc. of tions of spreading and dispersing agents, for example, water 0.75 gram of N-Inethyl-para-amino-phenol, 3 saponin, and/or aqueous solutions of hardening agents grams of hydroquinone, grams of sodium sulfite, can be added to the mixture. 40 grams of sodium carbonate and 1 gram of potas- 10 cc. of an emulsion so prepared are cast on a glass sium bromide; plate measuring 13 x 18 cm. and dried. The layer is ex- (2) Washed for three minutes; posed beneath a black and white positive image and the (3) Fixed for 5 minutes in a solution containing 200 silver image developed in a bath which contained in 1000 grams of sodium thiosulfate and 20 grams of potasparts of water, 80 parts of anhydrous sodium sulfite, 55 sium meta-bisulfite per liter of water; parts of anhydrous sodium carbonate, 20 parts of sodium (4) Washed for 5 minutes; borate and 8 parts of N-methyl-para-aminophenol sulfate. (5) Hardened for 5 minutes with an aqueous solu- Development takes 4 to 6 minutes. The layer is given a tion of formaldehyde of 4% strength; short wash with water and then fixed for 5 minutes in a (6) Washed for 5 minutes; bath which contains 200 parts of sodium thiosulfate dis- (7) The dyestuff image is bleached for 10 to 30 minsolved in 1000 parts-of water. The layer is again washed utes with a solution containing, per liter of water, 60 for 5 minutes. to 100 grams of postassium bromide, 40 to 75 grams The layer is then bleached for 2 to 5 minutes in a bath of thiourea, 35 to 80 grams of hydrochloric acid of which contains 60 parts of 32% hydrochloric acid, 10 30% strength and 0.001 gram of amino-hydroxyparts of potassium bromide, 6 parts of thiourea and 0.001 phenazine; I to 0.002 part of a-amino-3-hydroxyphenazine dissolved in (8) Washed for 10 minutes; 1000 parts of water. It is then washed with water for 5 (9.) The residual silver is bleached for 10 minutes minutes, and the unconsumed image silver converted into and the dyestuff is simultaneously converted into silver bromide by a treatment for 3 to 5 minutes in a bath its copper compound by means of a solution of 60 which contains-60 parts of crystalline copper sulfate, 60 grams of copper sulfate, 80 grams of potassium broparts of potassium bromide and 20 parts of 32% hydromide and 10 cc. of glacial actic acid per liter of chloric acid in 1000 parts of water. Water; (the yellowish-red tint changes towards blue- After a short wash with water, the layer is fixed for 5 red, especially markedly after bath No. 10); minutes in a bath which contains 100 parts of sodium 10) Washed for 5 minutes; thiosulfate in 1000 parts of Water, and again washed. The FiXed 5 minutes as described in 3 above; and image is then treated for 5 minutes in a bath which con- (12) Washed for 10 minutes. tains 25 parts of copper sulfate in 1000 parts of water. Aft being dried, the layer has a bluish red image f The layer is then given a final wash for 3 to 5 minutes.

good fa t to light A positive black and white image is obtained which is By using instead of the aforesaid dyestulf No. 2, the a pli e of the r g n having fi r l grey interdyestutf of the formula mediate tones. This image is distinguished by a high descan HO S NH 'HN u Hoooomo OCHZCOOH g c N N=C O C:

be. me

- 15 1Q gree of transparency of the grey gradations and by free- What is claimed is: dom from grain. By using a panchromatically sensitized 1. A photographic silver halide gelatine layer for the emulsion positive copies in black and white can be obsilver dyestuff bleaching method containing as an image tained from a positive color transparency. dyestuff an azoxy dyestufi of the formula i W H03sR; N=N-R5-N=1 1- oH=oH-O1 I=NR5N=N-R4s03n o $0311 Ho e Example 4 wherein R and R each represent a monocyclic benzene The following layers are poured on top of each other, radical bound in ortho-position to the azo group and the in the sequence shown, on to a white pigmented cellulose OCuO-group, the azo and azoXy-groups being acetate film: bound in para-position to the benzene radicals R 2. A photographic silver halide gelatine layer for the silver dyestuif bleaching method containing as an image dyest-ufi an azoxy dyestuff of the formula (1) A red sensitized silver bromide emulsion containing the greenrblue dyestuff of Formula 20. (2) A thin gelatine intermediate layer.

OOu-0 O-Cu-O I l l l HOaS O 0 $0311 OZ so3H H035 zo (3) A green sensitized silver bromide emulsion with the wherein Z represents an alkyl group having at most 2 magenta dyestulf of the formula carbon atoms.

NH; Hogs soan Hm i i i N=NC NHGC NHCNH-:C CHN N=N- 0H BIO- HO3|S S OaH 3. A photographic silver halide gelatine layer for the silver dyestulf bleaching method containing as an image dyestutf an azoxy dyestuff of the formula w Ro-NN N=NOIE=N -N=N NHRo S0311 HOaS (4) A filter layer with the dyestufi of the formula wherein R represents a monocyclic benzene radical.

, SOaH 4. A photographic silver halide gelatine layer for the 0 silver dyestutf bleaching method containing as an image @0112 dyestufi an ozoxy dyestutf of the formula Ha (5) An unsensitized silver bromide emulsion with the wherein R represents a monocyclic benzene ring bound dyestuff of the formula to the azo group in 1-position and to the azoxy group in 1103s SOaH S OaH HOQ S The material is exposed, fixed and hardened, then v bleached in a dyestuif bleaching bath containing hydro- 4-position and containing in 2-position a substituent sechloric acid, potassium bromide, thiourea and Z-aminolected from the group consisting of an alkoxy group and 3-hydroxyphenazine, and finally freed. from excess silver. a hydroxy-alkoxy group containing at most 5 carbon An image corresponding to the copy is obtained. The atoms, and R and R each represent the radical of an dyestuif of Formula 20 is found to be fast to diffusion, 8-hydroxynaphthalene-disulfonic acid bound to the azo bleached pure white at the areas of maximum density group in its 7-position and containing in its l-position a of silver and shows a good fastness to light. member selected from the group consisting of a phenyl- Similar results can be obtained with the dyestuffs of amino group, a cyclohexylamino group, a benzoylamino Formulae 21, 22, 23, 25, 26 and 27 instead of with the group, a para-toluenesulfonylamino group and a 1-(3'- dyestuif of Formula 20, carboxy-4'hydroxybenzenesulfonylamino) group.

5. A photographic silver halide gelatine layer for the wherein X represents a member selected from the group silver dyestufi bleaching method containing as an image i f oftan grgup i hyd'ofiyalkoxy i con aimng a mos car on a oms' an 9 represen s a dyestuff an azoxy dyestutf of the formula monocyclic benzene radicaL v A OH X X HO A 0 Y- SOaH HOaS- Y i i wherein A and A each represents a member selected 8. A photographic silver halide 'gelatine layer for the from the group consisting of a phenylamino group, a 15 silver dyestufi bleaching method containing as an image cyclohexylamino group, a benzoylamino group, a paradyestufi the azoxy dyestuff of the formula toluenesulfonylamino group and a 1-(3'-carboxyl-4hy- I 9. A photographic silver halide gelatine layer for the droxybenzenesulfonylamino) group, X represents a memsilver dyestulf bleaching method containing as an image ber selected from the group consisting of an alkoxy group dyestutf the azoxy dyestufi of the formula v NH 7 HN HOOCH;CO 0-CH -OOOH n C I CN=N Il [I=N J N=NCH I N=C v O. \C= N I v and a hydroxyalkoxy group containing at most 5 carbon I 1 atoms, and in each naphthalene radical one Y represents 10. A photographic silver halide gelatine layer for the a hydrogen atom and the other Y represents a sulfonic 35 silver dyestufi? bleaching method containing as an image acid group. .Hdyestuff the azoxy dyestuff of the formula HgN OH HgC-O O 'CHQ HO NH,

HOa S 6. A photographic silver halide gelatine layer for the silver dyestutf bleaching method containing as an image dyestuif an azoxy dyestufi of the formula acyl hll'H (|)H Iii HO HN-acyl o v HO3S SO3H HO3S- SOaH wherein X represents a member selected from the group 11. A photographic silver halide gelatine layer for the consisting of an alkoxy group and a hydroxyalkoxy group silver dyestuff bleaching method containing as an image containing at most 5 carbon atoms. dyestufi the azoxy dyestufi of the formula 7. A photographic silver halide gelatine layer for the silver dyestulf bleaching method containing as an image dyestuif an azoxy dyestufif of the formula R9SO2NH OH X X HO HN-SOr-Rn HO S O H O HO S a S a a S 03 3,211,556 19 20 12.A photographic silver halide gelatine layer for the silver dyestufi bleaching method containing as an'image dyestuifthe 'azoxy dyestuff of theformula mN 011 H000 1 00011 HO NH:

| a ma MPGI M MM M HOa S 503R 13. A photographic silver halide gelatine layer for the silver dyestufl? bleaching method containing as an image dyestufi the azoxy dyestufi of the formula OCu-0 I 0 Cu 0 H035 OCH3 SO3H H038 I H3C--O $0311 14. A photographic silver halide gelatine layer for the silver dyestufi? bleaching method containing as an image 20 dyestuif the azoxy dyestufi' of the formula" 0 HQaS SOaH HOaS- 503E 15. A photographic silver halide gelatine layer for the silver dyestuif bleaching methd containing as an image dyestufi the azoxy dyestuflf of the formula Hic C -so, 1 n on Him-( o-QH, H H1 I-o,sC -0H3 HOaS- 80 11 I O H03s sea 16. A photographic silver halide gelatine layer for the silver dyestnfi bleaching method containing as an image dyestutf the aaoxy dyestuff of the formula 40 HO S- SOaH HOaS'f 803E References Cited by the Examiner UNITED STATES PATENTS 2,987,513 6/61 schmidt et a1 260-143 3,148,062 9/64 Whitmore et a1 96-100 NORMAN Q. 'IORCHIN, Primary Examiner. I

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent Non 3, 211,556 Octobel" 12, 1965 Walter Anderau corrected below.

Column 16, claim 3, for that portion of the formula reading R NN read R HN column 17, claim 5, line 4 after the carboxy1-4hy-" rea formula, for "l(3'- line 30, for "methd" l- (3 -carboxy-4 hycolumn 19, read method d this 26th day of July 1966.

(SEAL) Attest:

ERNEST W. SWIDER EDWARD J. BRENNER Attesting Officer Commissioner of Patents 

4. A PHOTOGRAPHIC SILVER HALIDE GELATINE LAYER FOR THE SILVER DYESTUFF BLEACHINGMETHOD CONTAININ AS AN MAGE DYESTUFF AN AZAXY DYESTUFF OF THE FORMULA R8-N=N-R7-N(=O)=N-R7-N=N-R8'' WHEREIN R7 REPRESENTS A MONOCYCLIC BENZENE RING BOUND TO THE AZO GROUP IN 1-POSITION AND TO THE AZOXY GROUP IN 4-POSITION AND CONTAINING IN5-POSITON A SUBSTITUENT SELECTED FROM THE GROUP CONSISTING OF AN ALKOXY GROUP AND A HYDROXY-ALKOXY GROUP CONTAINING AT MOST 5 CARBON ATOMS, AND R6 AND R8'' EACH REPRESENT THE RADICAL OF AN 8-HYDROXYNAPHTHALENE-DISULFONIC ACID BOUND TO THE AZO GORUP IN ITS 7-POSITION AND CONTAINING IN ITS 1-POSITION A MEMBER SELECTED FROM THE GROUP CONSISTING OF A PHENYLAMINO GROUP, A CYCLOHEXYLAMINO GROUP, A BENZOYLAMINO GROUP, A PARA-TOLUENESULFONYLAMINO GROUP AND A 1-(3''CARBOXY-4''-HYDROXYBENZENESULFONYLAMINO)GROUP. 